Worth keeping in mind in future, when creating a broad scope that would encompass legal professional privilege material (which includes advice given by in-house lawyers to the Secretary and other office holders, and certainly would cover the advices you sought copy of here), that such documents would be exempt under s 42 of the Act from production.

In future, you should consider making an administrative request for such information, because it there was any intent by an agency to voluntarily wave LPP, they would do so quicker and without as much resource demand on the agency via administrative release.

It seems from your scope that you also sought any advice DHS may have provided other agencies on this topic. Such policy formulation/advice to external agencies on FOI would not be a function of DHS, but rather come from AGD or APSC or PMC or OAIC (although OAIC would be advisory only). You may like to ask them if they have ever done so.

It is always a good idea to read the FOI Guidelines, take a look at the AGD FOI resources for agencies, and consider not only the nature of the documents sought (remember FOI isn’t a right to information really, but rather documents), but how to not waste the time of the agency due to poor scope definition (if you make it easier for them, you’ll have more chance of them making an accurate search).

Good luck, and take the opportunity to look at the successful FOI applications here on Right to Know, and you’ll soon learn how to improve your technique.